heart lung machine pump

7/31/2019 Heart Lung Machine Pump

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HEART LUNG MACHINE

PUMP



What is It ?

A medical equipment that providesCardiopulmonary bypass, (temporary

mechanical circulatory support) to the

stationary heart and lungs)

Heart and Lungs are made “functionless

temporarily” , in order to perform surgeries CABG

Valve repair Aneurysm

Septal Defects



History

Lewis and Taufic first used the HypothermiaApproach clinically on September 2, 1952.

Under moderate total body hypothermia,

Lewis and Taufic used a short period of

circulatory arrest to repair a congenital defectin a 5 year-old girl.

An alternative approach named Cross-

Circulation was used by Dr. C. Walt whenon March 26, 1954,when he repaired a VSD

in a 12 month-old infant.



On May 6, 1953, Dr. Gibbon used his heart –

lung machine to successfully repair an atrial

septal defect in an 18 year-old girl,

Marking the first successful clinical use of a

Heart –Lung Machine



Modified – Mayo Clinic (1955)



Present Day Machine



Principles and Necessity

Heart is Stopped

Blood diverted through

tubes and is pumped

to maintain flow

Temperature regulation of blood

and gaseous exchange is done

Blood circulated systemicallybypassing the heart

and lungs



Cardioplegia

The intentional and temporary cessation of cardiac

activity.

Common procedure for accomplishing asystole is

infusing cold crystalloid cardioplegia into thecoronary circulation. Iced (4 degrees Celsius)

solution of dextrose, potassium chloride, and

Magnesium rich solution is introduced via

specialized Cannula. B05XA16

MeSH

http://en.wikipedia.org/wiki/ATC_code_B05

http://www.whocc.no/atcddd/indexdatabase/index.php?query=B05XA16

http://en.wikipedia.org/wiki/Medical_Subject_Headings

http://en.wikipedia.org/wiki/Medical_Subject_Headings

http://www.whocc.no/atcddd/indexdatabase/index.php?query=B05XA16

http://en.wikipedia.org/wiki/ATC_code_B05



Parts

Five pump assemblies Venous Cannula

Arterial Cannula - dual-stream aortic perfusion

catheter / meshed cannula

Venous Reservoir

Oxygenators

Heat Exchangers

Cardiotomy Reservoir and Field Suction Filters and Bubble Traps

Tubing and Connectors



Pumps

Centrifugal pumps consist of plastic cones,which when rotated rapidly, propel blood bycentrifugal force.

Forward blood flow, varies with the speed of rotation and the after load of the arterial line.

Centrifugal blood pumps generate up to 900mm Hg of forward pressure, but only 400 to500 mm Hg of negative pressure. Hence,less gaseous micro emboli.

Centrifugal pumps produce pulse less blood

flow

Centrifugal

Roller



Roller pumps consist tubing, which is

compressed by two rollers 180° apart.

Forward flow is generated by roller

compression and flow rate depends upon thediameter of the tubing, rate of rotation.



Impeller PumpRoller Pump Centrifugal Pump



Five pump assemblies :

A centrifugal or roller head pump can be used in the

arterial position for extracorporeal circulation of the

blood.

Left ventricular blood return is accomplished byroller pump, drawing blood away from the heart.

Surgical suction created by the roller pump removes

accumulated fluid from the general surgical field.

The cardioplegia delivery pump. Emergency Backup of the arterial pump in case of

mechanical failure.



Venous Reservoirs

Reservoirs may be rigid (hard) plastic canisters

("open" types) or soft, collapsible plastic bags

("closed" types).

The venous reservoir serves as volume reservoir Facilitates gravity drainage,

Venous bubble trap present,

Provides a convenient place to add drugs, fluids, or

blood, and adds storage capacity for the perfusionsystem.



Oxygenators

Membranous

Bubble



Membranous Oxygenators

Imitate the natural lung by interspersing a thinmembrane of either micro porouspolypropylene or silicone rubber between thegas and blood phases.

With micro porous membranes, plasma-filledpores prevent gas entering blood but facilitatetransfer of both oxygen and CO2.

The most popular design uses sheaves of hollow fibers connected to inlet and outletmanifolds within a hard-shell jacket.



Bubble Oxygenators

Venous blood drains directly into a chamber into

which oxygen is infused through a diffusion plate

(sparger).

The sparger produces thousands of small(approximately 36 µm) oxygen bubbles within blood.

Gas exchange occurs across a thin film at the blood-

gas interface around each bubble

Produce more particulate and gaseous microemboliare more reactive to blood elements.



Heat Exchangers

Control body temperature by heating or

cooling blood passing through the perfusion

circuit

Temperature differences within the body and

perfusion circuit are limited to 5°C to 10°C to

prevent bubble emboli



Filters and Bubble Traps

In the circuit, micro emboli are monitored by

arterial line ultrasound or monitoring screen

filtration pressure.

Depth filters consist of porous foam, have alarge, wetted surface and remove micro

emboli by impaction and absorption

Screen filters are usually made of wovenpolyester or nylon thread.



Tubing

Medical grade Polyvinyl Chloride (PVC) tubing

It is flexible, compatible with blood, inert,

nontoxic, smooth, nonwettable, tough,transparent, resistant to kinking and collapse,

Can be heat sterilized

The Duraflo II heparin coating ionicallyattaches heparin to a quaternary ammoniumcarrier (alkylbenzyl dimethyl - ammoniumchloride), which binds to plastic surfaces.



Perfusion Monitors and Sensors

A low-level sensor with alarms on the venousreservoir and a bubble detector on the arterial

line are desirable safety devices.

Flow-through devices are available to

continuously measure blood gases,hemoglobin/hematocrit , and some electrolytes

Temperatures of the water entering heatexchangers



Sterilization :

Ethylene dioxide is commonly used

4 hours of sterilization at 55°C or 18 hours at22°C .

Disadvantages of ethylene dioxide , are thetoxicity and explosive nature

Disposable tubing ,reservoirs and oxgenator Steam sterilization as PVC can withstand

heat



Disadvantages

Post perfusion Syndrome - a transient

neurocognitive impairment associated with

cardiopulmonary bypass. Some research

shows the incidence is initially decreased byoff-pump coronary artery bypass

http://en.wikipedia.org/wiki/Postperfusion_syndrome

http://en.wikipedia.org/wiki/Off-pump_coronary_artery_bypass




http://en.wikipedia.org/wiki/Postperfusion_syndrome



Off Pump CABG



The Future !!

CARDIOARM

Carnegie Mellon University



References

Cohn LH, Edmunds LH Jr, - Cardiac Surgery in the Adult

Wiley - Encyclopedia of Medical Devices and Instrumentation - Vol. 3

Joseph Carr , Brown –

4 th edition Cardiopulmonary Bypass: Principles and

Practice, 2nd edition - Gravelee, Glenn P.,Richard F. Davis, Mark Kurusz, and Joe R. Utley

Sterilizing procedures for heart-lung machines - J. C. Kelsey

heart lung machine pump

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